Liquid state Dynamic Nuclear Polarization probe with Fabry-Perot resonator at 9.2 T
- 作者：Vasyl Denysenkov ; Thomas Prisner ; Prisner@Chemie.Uni-Frankfurt.de
- 关键词：Dynamic Nuclear Polarization (DNP) ; Electron paramagnetic resonance (EPR) ; Nuclear magnetic resonance (NMR) ; DNP spectrometer ; Double resonance structure ; High magnetic fields
- 刊名：Journal of Magnetic Resonance
- 出版年：2012
- 期刊代码：126_10907807
- 类别：ch
- 出版时间：April, 2012
- 卷：217
- 期：Complete
- 页码：1-5
- 文件大小：731 K
摘要
Recent achievements in liquid state DNP at high magnetic fields showing significant enhancements on aqueous solutions have initiated strong interest in possible applications of this method to biomolecular research. However, in situ DNP of biomolecules at ambient temperatures is a challenging task due to high microwave losses leading to excessive sample heating. To avoid such heating the sample volume has to be reduced strongly to keep it away from the electric component of the microwave field. A helical double resonance structure, used for the first demonstrations of the applicability of Overhauser DNP to aqueous solutions at high magnetic fields (9.2 T), restricted the sample size to a very small volume of 2 nl. Together with a poor spectral resolution this resulted in small overall signal amplitude, hampering observations of biomolecules. Here we present a new type of the double resonance structure for liquid-state DNP which consists of a Fabry-Perot resonator for the microwave excitation and a stripline resonator for the NMR detection. This new double resonance structure (260 GHz/400 MHz) offers a 30-fold increase in aqueous sample volume (80 nl) with respect to the helical probe and exhibits improved NMR sensitivity and linewidth.